Q1: Pick up the correct statement from the following :

ANS:E - All the above.

The correct statement from the options provided is: "All the above." Each statement listed is accurate:

1. The ratio of the quantity of diluting water to that of the sewage is indeed known as the dilution factor.
2. The automatic purification of polluted water is indeed known as the self-purification phenomenon.
3. Photosynthesis does occur in the presence of sunlight.
4. Grab samples are generally obtained from the surface where turbulence mixes the sewage particles.